The present disclosure relates to a body-control-device for a bi-directional transistor, and in particular to a body-control-device that includes a negative-voltage-source that can provide a negative voltage bias between a body-control-terminal and a first-body-channel-terminal (such as a source terminal) of the bi-directional transistor.
A bi-directional MOSFET is a device with a blocking voltage for both, positive and negative biasing. A trench gated realization includes buried p-body layer separated from a n+ source terminal with a top drift n-epi layer. Between an n+drain terminal (n+sub) and a p− body is located a bottom n-epi layer. The device structure forms two inherent pn junctions and respectively two diodes. Using an n-channel formed at the vertical Si/SiO2 interface to result in positive bias applied to the gate terminal, inverses locally the buried p-doped body. The forward and reverse blocking of the device can be defined by the space charge widths and doping, respectively in the bottom and top n-epi layers. The bi-directional device can integrate the blocking function of two serial standard mono-directional MOSFETs in one device assembled in one package with up to 4× improvement of specific Rdson (drain-source resistance when the transistor is ‘on’) using one gate driver circuit.